Sovereignty, privacy and backup are the foundation, not an afterthought.
A powerful personal system is worthless if you don't own and protect what's in it — sovereignty, privacy and backup are the foundation everything else sits on.
This is the unglamorous rung, and skipping it is how people lose a decade. Every capability in this system — the graph, the reasoning, the derived insight — assumes the data will still be there and still be yours. That assumption is doing enormous work, and it's the one nobody stress-tests until the day it fails.
Three things, none optional. Sovereignty: you can take it all and leave, today, without asking. Privacy: a model of your life is the most sensitive dataset you'll ever hold, and it shouldn't be someone's training corpus. Backup: the only real test is whether you've restored from it recently.
Foundations are boring until they aren't. Everything above them is a rounding error if they give.